Lower hybrid range cold magnetized plasma coupling in ANSYS HFSS

The coupling between cold magnetized plasmas with lower hybrid resonance frequency antennas is generally addressed using specifically developed codes. These antenna coupling codes often approximate the plasma to a surface impedance described by a 1D half infinite models and antennas either with simplified 2D dimensions or from 3D CAD models conversion. Such approaches add an additional step of model approximation/conversion which is not convenient to rapidly assess impact of geometry changes on coupling performances. In this work, we assess the ability of using ANSYS HFSS to describe the usual range of experimental magnetized cold plasma inhomogeneous parameters facing LHRF antennas, away from resonances, in order to guide the RF designer during the design phase of an antenna. The coupling calculations of Lower Hybrid Resonance Frequency antennas are performed and successfully benchmarked with the fast coupling codes ALOHA on inhomogeneous cold magnetized plasmas. Good agreements are obtained when the boundary conditions in the full-wave modelling are properly handled. Practical advices and limitations are given in order to define correctly these boundary conditions and insure correct results.